Endangered Hawaiian Songbird Hatched in Artificial Nest Box Raises Hope for Species’ Survival

There is renewed hope for conservation of the endangered Puaiohi (pronounced Poo-eye-o-hee; also known as the Small Kauaʻi Thrush) on the island of Kauaʻi, Hawaii. Nest boxes put up in 2007 by Pacific Rim Conservation and the Kauaʻi Forest Bird Recovery Project have recently resulted in the fledging of a chick. This event is only the second time ever that Puaiohi chicks have fledged from nest boxes in the wild. Furthermore, during checks at the end of the season, fresh nest material was found in three other nest boxes, indicating that Puaiohi have been actively exploring and perhaps using even more nest boxes.

Puaiohi in nestbox by Eric VanderWerf, Pacific Rim Conservation

Puaiohi in nestbox by Eric VanderWerf, Pacific Rim Conservation

“When there are only approximately 500 mature individuals of a species left, small successes such as this are reasons to be excited.  It looks like the team on Kauaʻi may have identified a methodology that, though labor intensive, offers additional hope for preserving this bird in the wild,” said George Wallace, Vice President for Oceans and Islands at American Bird Conservancy.

The Puaiohi nests in natural cliff and tree cavities, and like many other native Hawaiian bird species, it is highly vulnerable to nest predation by rats, which prey on eggs, chicks, and even adults. A key to the success of some of these nest boxes, placed along the Kawaikoi Stream located in the Na Pali-Kona Forest Reserve and the Halepaʻakai Stream in the Alakaʻi Wilderness Preserve, is that they provide nest sites that are safer from rats.  Lisa “Cali” Crampton, Project Leader for the Kauaʻi Forest Bird Recovery Project, which is implementing conservation efforts for the Puaiohi said that, “Eventually, the project hopes to expand the range of Puaiohi by providing nest boxes in other areas that lack the natural cliff nest sites preferred by the species.”

One nest fledged a chick early in June, the first and only time since the first successful fledging in 2002. A second nest box was used for nesting, but the nesting attempt failed.  “Although only a small number of the 34 boxes have been used so far, we’re hoping that this is the beginning of an encouraging trend,” said Eric VanderWerf of Pacific Rim Conservation, who installed the boxes in 2007.

The Puaiohi is endemic to a small part of the island of Kauaʻi and is listed under the Endangered Species Act as Endangered. In addition to the rat problem, pigs destroy native forest understory vegetation where Puaiohi spend much of their time. Non-native plants, such as blackberry, Australian tree fern, Kahili ginger, daisy fleabane, and strawberry guava make habitat unsuitable for Puaiohi, in some cases overwhelming the cliff nesting sites along preferred stream banks with vegetation.

Puaiohi are also susceptible to avian pox and avian malaria, which are transmitted by introduced mosquitoes, but the full extent to which those diseases limit the species is not fully understood. Some birds have recently exhibited resistance to malaria, which is very encouraging for the future survival of the species.

The recovery efforts for Puaiohi are led by the Kauai Forest Bird Recovery Project, a cooperative project of Hawaii’s Division of Forestry and Wildlife (DOFAW) and the Pacific Cooperative Studies Unit of the University of Hawaii, and are supported by partners including the Kokeʻe Resource Conservation Program and the Kauai Watershed Alliance. Puaiohi have done relatively well in captivity. The Zoological Society of San Diego, in partnership with DOFAW and the U.S. Fish and Wildlife Service, have bred and released nearly 200 Puaiohi into the wild since 1999, which has likely helped maintain the wild population. In fact, some of the nest boxes in Kawaikoi Stream were used by captive-bred birds, further bolstering prospects for the species’ recovery.